Several animal studies have disclosed that the electrical stimulation of the fastigium nucleus (FN), which forms a portion of the cerebellum, can have dramatic effects on reducing the core infarction size and surrounding penumbra after the onset of an ischemic stroke. For example, one study suggests that the stimulation of the FN for just one hour provides ten days worth of neuroprotection. Another study suggests that the infarction volume can be reduced by at least forty percent when the FN is stimulated after a stroke. The mechanism used to provide neuroprotection via FN stimulation is not well understood, but the studies have suggested that stimulation of the FN suppresses tissue damaging inflammation of brain tissue otherwise brought on by the overproduction of enzymes in response to the ischemic event. In all of the animal studies, the FN was electrically stimulated via a highly invasive surgical procedure.
Currently, the stimulation treatment of various neurological disorders in humans, including ischemic stroke, as well as Alzheimer's Disease, Parkinson's Disease, Tremor, and Epilepsy, can be accomplished via a substantially invasive procedure, which involves first drilling a burr hole through the patient's cranium in order to gain access to the brain tissue. A stimulation lead, and in particular, a lead with multiple electrodes extending along its length, is then introduced through one or more burr holes into contact with the selected brain tissue. In a deep brain stimulation (DBS) procedure, typically used to treat Parkinson's Disease, Tremor, and Epilepsy, the stimulation lead is advanced through a burr hole deep into the brain, e.g., the anterior thalamus, ventrolateral thalamus (Thal), internal segment of globus pallidus (GPi), substantia nigra pars reticulata (SNr), subthalamic nucleus (STN), external segment of globus pallidus (GPe), and neostriatum. In a cortical brain stimulation procedure, typically used to rehabilitate stroke victims, the lead is introduced through two burr holes and placed underneath the dura matter in contact with the cortex of the brain.
Once the lead is properly located in contact with the selected brain tissue, an electrical stimulator can be connected to the lead and operated to convey therapeutic electrical energy to the selected brain tissue. Depending on the period of treatment, the electrical stimulator may be implanted, in which case, the proximal end of the lead or an extension lead can be subcutaneously routed from the burr hole underneath the patient's scalp, down the neck, and into the chest or abdominal region in electrical connection with an implanted electrical stimulator.
Although the current brain stimulation techniques used to treat neurological disorders have proven to be successful, none of the previous techniques suggest a less invasive approach for stimulating the FN to treat ischemic stroke. That is, such techniques are still quite invasive, requiring the cranium to be opened through at least one burr hole, and entirely delivered through brain tissue to reach the stimulation site.
Thus, there remains a need to provide an improved method of electrically stimulating the FN to treat neurological disorders, such as ischemic stroke.